A tilt position adjustment mechanism is a mechanism for adjusting an inclination angle of the steering wheel to the best driving position according to the body type or preference of the driver. In adjusting the inclination angle of the steering wheel, after the inclination angle of the steering wheel is adjusted steplessly in a state where a tilt clamp mechanism is unclamped once, the tilt clamp mechanism is again clamped.
In the steering device having the steering position adjustment mechanism of this type, a vehicle body attachment bracket is fixed to a vehicle body, and a fastening rod is allowed to insert into a tilt adjustment slender groove and a column of the vehicle body attachment bracket. During tilt clamping, a stationary cam is pressed in an axial direction by a movable cam that rotates due to the operation of an operating lever to fasten the fastening rod, and the column is pressed toward the vehicle body attachment bracket for clamping. However, when the fastening force of the fastening rod is low, the column is caused to move in a tilt direction during a secondary collision where a driver collides with the steering wheel, resulting in a risk that an air bag disposed in the steering wheel cannot accept an occupant at an effective position.
As a mechanism for blocking the movement of the column during this secondary collision, there is a tilt lock mechanism in which a stationary tilt lock gear is disposed on the side plate of the vehicle body attachment bracket, and a movable tilt lock gear the is engaged with the stationary tilt lock gear is inserted into the fastening rod.
With this configuration, during the tilt locking, the fastening rod is fastened by the operation of the operating lever to engage the movable tilt lock gear with the stationary tilt lock gear, thereby improving a retention force in the tilt direction, with the result that even if an impact load due to the secondary collision is exerted on the steering wheel, the column is not moved in the tilt direction.
In the above steering device that improves the retention force in the tilt direction, when the tilt clamp is conducted, the movable tilt lock gear contacts the outer surface of the side plate of the vehicle body attachment bracket, and slides. Also, during the tilt unclamping, because the movable tilt lock gear is bumped, the movable tilt lock gear is abutted against the outer surface of the side plate of the vehicle body attachment bracket. Because the movable tilt lock gear and the vehicle body attachment bracket are each made of metal, the sliding sound where metal is rubbed with each other during the tilt clamping occurs. During the tilt unclamping, an impact sound where the movable tilt lock gear is abutted against the outer surface of the side plate of the vehicle body attachment bracket occurs.
In a steering device of Patent document 1, the stationary cam and the locking unit made of a synthetic resin are formed integrally, as a result of which smooth sliding of the stationary cam during the tilt position adjustment, and an impact sound when the protrusion of the stationary cam is abutted against the groove end of the tilt position adjustment slender groove at the tilt position adjustment end is reduced.
However, a steering device of Patent document 1 is intended to reduce the sliding sound and the impact sound between the stationary cam and the tilt position adjustment slender groove, but not intended to reduce the sliding sound and the impact sound between the movable tilt lock gear and the outer surface of the side plate of the vehicle body attachment bracket.